This invention relates to compositions of 2-(thiocyanoethylthio)benzothiazole (TCMTB) and at least one trihalogenated phenol for the purpose of controlling the growth and reproduction of microorganisms.
More particularly, the invention relates to compositions containing TCMTB and at least one trihalogenated phenol to inhibit the growth of fungi and bacteria in industrial processes and products. For example, fungi are traditionally classified as a subdivision of the Thallophyta of the plant kingdom and are saprophytic or parasitic, i.e., fungi must derive their nutrition from a preformed source of organic carbon. Spore dispersal mechanisms among the fungi provide an effective means of extending the species to sources of organic and mineral nutrition, provided that existing temperature and moisture conditions are conducive for growth of the organism.
The spores germinate into vegetative hyphae which are capable of degrading the organic substrate on which they are growing, yielding smaller and simpler subunits These in turn are absorbed into the body of the fungus whereby they are metabolized, and the organism derives nutrients or builds cellular structures.
Such degradative processes are important in nature because they constitute a means of recycling organic debris which collects on the surface of the earth However, other vehicles of nutrition are provided by industry since fungi do not discriminate between what is perceived by man to be harmful versus what is perceived to be beneficial.
One such source of energy is raw, unseasoned wood produced from the activities of sawmills The cut logs represent a rich source of organic and inorganic compounds contained within a moist cellulosic matrix. At sawmills, raw or freshly cut lumber is characteristically stacked outdoors for air drying (cure).
During this relatively slow process of drying, the lumber is continuously being contaminated with fungal spores whose germination and growth on the wood surface may lead to significant economic loss to the sawmill as a result of surface disfigurement due to sapstain and/or mold. In addition, other fungal species may contaminate the wood and then actually decay or diminish the structural integrity of the wood by enzymatically hydrolyzing the cellulose and/or lignin within the primary and secondary cell walls.
In the lumber industry, these fungal problems are controlled through the application of chemicals to the freshly cut wood. Among commercially available chemicals which have experienced use in this industry are pentachlorophenol (PCP), 2-(thiocyanomethylthio) benzothiazole (TCMTB) (available commercially from Buckman Laboratories, Inc.), 3-iodopropynylbutylcarbamate (IPBC), and disodium octaborate tetrahydrate (available commercially as Tim-Bor.RTM.)
Some of the organic fungicidal agents, such as PCP, are the objects of increasing environmental concern resulting in legal restrictions on, or complete banning of, their usage. The discovery of synergistic combinations of chemicals which include TCMTB provides an opportunity to achieve a desired level of protection of wood against fungal spoilage at a reduced quantity of chemical consumption and at a potentially lower cost.
The chemical TCMTB is a known fungicide which is used commercially for the protection of freshly cut lumber against mold and sapstain. Combinations of TCMTB with other fungistatic materials to provide synergistic compositions have been reported for bis-trichloro-methyl-sulfone (U.S. Pat. No. 4,479,961), 3-iodopropynyl--N-butyl carbamate (Japan Pat. No. 63,101,305), and methylene-bisthiocyanate (Japanese Patent No. 61,041,501). Additional patents have described the use of 2,4,6-tribromophenol alone or in combination with other substances for wood protection (Japan Pat. Nos. 58,118,505, 56,075,412 and 55,059,907).
None of these patents, however, describes the combination of TCMTB and at least one trihalogenated phenol, such as 2,4,6-tribromophenol. The composition of this invention contains TCMTB and at least one trihalogenated phenol and, preferably, a synergistic combination of TCMTB and at least one trihalogenated phenol. These compositions can be effective for controlling microbiological growth and particularly fungal growth.
The compositions of the invention can protect surfaces in general against microorganisms such as fungi. Representative surfaces which can be protected include wood, leather, textiles paint, plastics, paper and pulp which are subject to attack by microorganisms such as fungi. The compositions can also inhibit the growth of microorganisms, such as bacteria and fungi in liquid and solid substrates, such as dyes, pastes and adhesives, and, particularly in liquid and solid substrates associated with industrial processes.